1. Field of Invention
This invention relates to systems for accessing the Internet. More specifically, this invention is directed to an Internet access system and method with active link status indicators.
2. Description of Related Art
Most distributive information networks, such as the Internet, utilize local caches to reduce the system response time. An Internet access system, such as a World Wide Web browser, generally has access to a local cache. When a user selects a Web link to request a document, the Web browser first determines if the requested document is present in the local cache. If the requested document is present in the local cache, the Web browser simply displays the copy of the document in the cache. If the requested document is not present in the local cache, the Web browser fetches the document from the Web, places the document in the local cache and displays the document to the user.
A cache may be shared by many users of the Web, or it may only be accessible to a single user. When the cache is shared by many users, a document that has been fetched by one user may be fetched from the cache in response to subsequent requests by other users. Therefore, when the cache is shared by a large number of users, most popular Web documents will already be cached when any given user requests the document. This reduces the amount of network traffic and also reduces the length of time that a user must wait for the document.
In standard Web browsers, the browser does not indicate to the user whether a document is present in the cache. Furthermore, the user has no control over placing a document into the cache. The only indication that a user has that a document has been cached is that a second fetch of the document is generally much faster than the first fetch.
Efforts have been made to reduce the transparency of the cache and to give the user more control over the cache. An Internet access system for portable computers, disclosed in Schilit et al., "TeleWeb: Loosely Connected Access to the World Wide Web," 5.sup.th International World Wide Web Conference, Paris, France, May 6-10, 1996, indicates Internet links to documents that are not cached in the portable computer with an icon. Thus, a user can defer attempts to fetch those documents until the portable computer is connected to the Internet.
The icons in the Schilit system tell the user that a document is not in the cache. However, the icons are not active and thus do not help the user load a document into the cache. Specifically, the Schilit system does not provide a mechanism for loading documents into the cache other than by fetching and displaying the documents in the usual fashion.
Goldberg et al., "How to Program Networked Portable Computers," IEEE #0-8186-4000, June 1993, pages 80-88, discloses an X-Window mail application that greys out the menus and buttons representing documents that are not in the local cache. When a user selects a document represented by a grayed-out menu or button, the system loads the document into the local cache.
A problem with the Goldberg system is that the technique of graying out the names of document links is not appropriate for Web browsers. One reason for this is that Web browsers currently use the display characteristics of Internet link names to represent other information. For example, when a user selects the name of a link, the link name changes color to indicate that it has been selected.
Another reason that the Goldberg system is not appropriate for Web browsers is that Internet links are being increasingly represented by graphical elements, i.e., pictures. Because of the variability of graphical elements, it is difficult to provide a standardized method of modifying their display characteristics.
In addition, the Goldberg system immediately displays the document that is loaded into the cache. Thus, the Goldberg system does not allow a user to view one document while another document is loaded into the cache.